Unless you regularly clean the water tank and connecting pipes in your motorhome, you could be opening yourself up to the risk of becoming ill while you’re out on the road.

Regularly refilling the tank with fresh water is simply not enough to prevent the build-up of harmful bacteria and biofilm that can take up residence in your tank and pipework.

Follow our guide to cleaning your motorhome water tank to learn how to maintain a safe, clean water tank and keep unwanted stomach upsets and illnesses at bay.

How long should I keep water in my tank?

Believe it or not, water can go off if kept in your water tank for extended periods of time. In non-carbonated mineral water, bacterial growth occurs in bottles just a few days after filling and storing at room temperature, a phenomenon known for more than 40 years! The hot summer months cause more rapid deterioration of water left standing in water tanks and, in some cases, unpleasant odours. Because water stagnates in enclosed spaces, bacteria have free rein to multiply at an alarming speed. It is advisable to not leave water sitting in your tank for more than three days. Even if you don’t drink the water, you could still become infected through showering, rinsing fruit and vegetables, cleaning your teeth, or by inhaling the water as vapour.

How do I clean my water tank?

Empty the water tank: Turn off the water pump and heater. Locate the tank drainage valve on the underside of your motorhome and open to let the water out. Close the valve once drained.

Prepare a cleaning solution: Follow manufacturer’s instructions.

Add prepared cleaning solution to the tank: Use a funnel, to avoid spillage and use a hosepipe to fill the rest of the tank with clean water.

Clean the pipes: Pump the cleaning solution and clean water through them. Then simply close the taps and let cleaning solution and water sit in the pipes as recommended on the cleaning solution instructions. This can vary from 1 – 24 hours.

Drain and rinse: Finally, drain the pipes and the water tank completely. Blow air through the pipes using an air mattress pump and rinse thoroughly with fresh, clean water.

What products should I use?

There are lots of products available on the market for cleaning your water tank. We’ve listed three of the most popular and trusted products for effective cleaning.

Eslan fresh water tank cleaner

A chlorine-free cleaner that disinfects and removes calcium buildup from tanks and pipework. Also ideal for disinfecting water containers. It is safe to dispose of in septic tanks and all other disposal systems.


A unique dual-purpose formula which both cleans and sterilises tanks, pipes, pumps, and taps. It eradicates bacteria, viruses, biofilm, algae and fungi with a powerful action that won’t harm the components in your water system.

Pro-Kleen fresh water tank cleaner

Eliminates algae and bacteria from water tanks and supply systems. It’s great for ‘overwintering’ caravans and motorhome water tanks to eliminate the stale taste and foul smells that can linger after you’ve brought it out of hibernation. Just 100ml of solution is required per 20L of tank capacity.

How often should I clean my water tank?

This process should be carried out at least twice a year, to reduce the risk of contamination.

How do I maintain my water tank?

Don’t fill your tank completely

This will prevent standing water in your tank from becoming stagnant. It will also reduce the payload weight of your motorhome while you’re on the road and play a part in reducing your overall fuel consumption.

Refill frequently

Rinse and refill your tank every 1-3 days, to reduce bacteria growth. Only fill with water that is marked as ‘drinking water’ on campsites. Run water through your pipes on a frequent basis to keep the pipes clean.

Empty your tank after each trip

Never leave water standing in your tank when you are not using your motorhome, even if there is only a week between trips.

Deep clean

Follow the cleaning steps mentioned above when you bring your motorhome out of winter storage, and again during the summer.

Is it safe to drink water from my water tank?

While you may take all the necessary precautions to keep your tank clean, you can’t always guarantee the quality of the water source, or the cleanliness of the taps or hoses on campsites. It is advisable to drink bottled water or boil water drawn from your motorhome water tank before drinking, to kill any harmful bacteria that may be present.

If you’ve found this article useful, you may want to check out other articles we have written with motorhome owners in mind. Why not visit our website for more interesting reads.

Disclaimer: The sole purpose of this article is to provide guidance on the topic covered. This article is not intended to give legal advice, it should not be relied upon. It should not be regarded as a comprehensive statement of the law and/or market practice in this area. We cannot guarantee the completeness or accuracy of the information contained in the external links, which were live at the date of publication.

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